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Test ID CYPZ 21-Hydroxylase Gene (CYP21A2), Full Gene Analysis

Useful For

Carrier screening and diagnosis of 21-hydroxylase deficient congenital adrenal hyperplasia (CAH) in individuals with a personal or family history of 21-hydroxylase deficiency, or as follow-up to positive CAH newborn screens and/or measurement of basal and adrenocorticotropic hormone- 1-24 stimulated 17-hydroxyprogesterone, androstenedione, and other adrenal steroid levels

 

May be used to identify CYP21A2 mutations in individuals with a suspected diagnosis of 21-hydroxylase deficient CAH when a common mutation panel is negative or only identifies 1 mutation.

 

In prenatal cases of ambiguous genitalia detected by ultrasound, particularly when the fetus is confirmed XX female by chromosome analysis.

 

This test code should also be used for known/familial variant analysis for CYP21A2. Due to the complexity of the CYP21A2 locus, site specific testing for known/familial variants is not offered for this gene.

Genetics Test Information

This test includes Sanger gene sequencing and multiplex ligation-dependent probe amplification to evaluate the CYP21A2 gene for carrier screening and diagnosis of 21-hydroxylase deficient congenital adrenal hyperplasia (CAH).

Highlights

This test aids in carrier screening and diagnosis of 21-hydroxylase deficient congenital adrenal hyperplasia (CAH).

 

Full gene sequencing and multiplex ligation-dependent probe amplification are used to detect the common pathogenic CYP21A2 variants, CYP21A2 full gene deletions, and rare CYP21A2 variants.

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
MATCC Maternal Cell Contamination, B Yes No
CULFB Fibroblast Culture for Genetic Test Yes No
CULAF Amniotic Fluid Culture/Genetic Test Yes No

Testing Algorithm

For prenatal specimens only: If amniotic fluid (nonconfluent cultured cells) is received, amniotic fluid culture will be added and charged separately. If chorionic villus specimen (nonconfluent cultured cells) is received, fibroblast culture will be added and charged separately. For any prenatal specimen that is received, maternal cell contamination studies will be added.

Method Name

Polymerase Chain Reaction (PCR) Amplification Followed by DNA Sequence Analysis and Gene Dosage Analysis by Multiplex Ligation-Dependent Probe Amplification (MLPA)

Reporting Name

CYP21A2 Gene, Full Gene Analysis

Specimen Type

Varies


Advisory Information


This test is a molecular analysis of the CYP21A2 gene and does not include biochemical analysis of steroids. For biochemical analysis for congenital adrenal hyperplasia (CAH) which includes cortisol, androstenedione and 17-Hydroxyprogesterone, see CAH21 / Congenital Adrenal Hyperplasia (CAH) Profile for 21-Hydroxylase Deficiency.



Additional Testing Requirements


All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis on the maternal specimen.



Shipping Instructions


Specimen preferred to arrive within 96 hours of collection.

 

Prenatal specimens can be sent Monday through Thursday and must be received by 5 p.m. CST on Friday in order to be processed appropriately.



Specimen Required


Specimen Type: Whole Blood

Container/Tube:

Preferred: Lavender top (EDTA)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

 

Prenatal Specimens

Specimen Type: Amniotic fluid

Container/Tube: Amniotic fluid container

Specimen Volume: 20 mL

Specimen Stability Information: Refrigerated (preferred)/Ambient

 

Specimen Type: Chorionic villi

Container/Tube: 15-mL tube containing 15 mL of transport media

Specimen Volume: 20 mg

Specimen Stability Information: Refrigerated

 

Acceptable

Specimen Type: Confluent cultured cells

Container/Tube: T-25 flask

Specimen Volume: 2 flasks

Collection Instructions: Submit confluent cultured cells from another laboratory.

Specimen Stability Information: Ambient (preferred)/Refrigerated


Specimen Minimum Volume

Amniotic Fluid: 10 mL; Blood: 1 mL; Chorionic Villi: 5 mg

Specimen Stability Information

Specimen Type Temperature Time
Varies Ambient (preferred)
  Frozen 
  Refrigerated 

Reference Values

An interpretive report will be provided.

Day(s) and Time(s) Performed

Performed weekly; Varies

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81405-CYP21A2 (cytochrome P450, family 21, subfamily A, polypeptide2) (eg, steroid 21-hydroxylase isoform, congenital adrenal hyperplasia), full gene sequence

81402-CYP21A2 (cytochrome P450, family 21, subfamily A, polypeptide2) (eg, congenital adrenal hyperplasia, 21-hydroxylase deficiency), common variants (eg, IVS2-13G, P30L, I172N, exon 6 mutation cluster [I235N, V236E, M238K], V281L, L307FfsX6, Q318X, R356W, P453S, G110VfsX21, 30-kb deletion variant)

 

Fibroblast Culture for Genetic Test

88233-Tissue culture, skin or solid tissue biopsy (if appropriate)

88240-Cryopreservation (if appropriate)

 

Amniotic Fluid Culture/Genetic Test

88235-Tissue culture for amniotic fluid (if appropriate)

88240-Cryopreservation (if appropriate)

 

Maternal Cell Contamination, B

81265-Comparative analysis using Short Tandem Repeat (STR) markers; patient and comparative specimen (eg, pre-transplant recipient and donor germline testing, post-transplant non-hematopoietic recipient germline [eg, buccal swab or other germline tissue sample] and donor testing, twin zygosity testing or maternal cell contamination of fetal cells (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CYPZ CYP21A2 Gene, Full Gene Analysis In Process

 

Result ID Test Result Name Result LOINC Value
37488 Result Summary 50397-9
37489 Result In Process
37490 Interpretation In Process
37491 Additional Information 48767-8
37492 Specimen 31208-2
37493 Source 31208-2
37494 Released By No LOINC Needed

Forms

1. CYP21A2 Gene Testing for Congenital Adrenal Hyperplasia Patient Information (T663) is required and available in Special Instructions

2. New York Clients: Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.